Thermoplastic containers are used to package and dispense numerous flowable substances, such as powders, pastes or liquids. Of special interest are squeezable containers, such as bottles or tubes formed of thermoplastic material which containers are squeezed, by application of pressure on the sidewall of the container, so as to dispense a flowable substance from an orifice in a neck formed on the container. In order to provide a thermoplastic squeeze container, the wall of the container must be formed of a thermoplastic material that will flex so as to enable forcing of the flowable substance therefrom. Generally, such thermoplastic squeeze containers, after squeezing, are retained in the shape formed when a flowable substance is dispensed, i.e. in a somewhat collapsed condition.
In certain instances, it is desirable to use a self-sealing or self-closing valve in combination with a thermoplastic squeeze container. Examples of such containers containing self-sealing valves are, for example, shown and described in U.S. Pat. No. 5,033,655 and U.S. Pat. No. 5,213,236. As described in these patents, a dispensing package may contain a self-sealing valve which securely seals upon cessation of pressure on the side wall of the container, so as to protect the contents thereof from the atmosphere, but upon squeezing of the side wall the contents will be dispensed. The use of a self-sealing valve in combination with a tube shaped container is suggested in U.S. Pat. No. 5,033,655 and illustrated generally in FIGS. 6 and 7 of that patent. In order to use such a self-sealing valve in a tubular container, however, the side wall of the tubular container must have a specific rigidity or thickness such that, while being squeezable, the side wall will return to the shape that existed before squeezing such that air will be sucked back into the container body so as to close the self-sealing valve. The formation of such thick-walled tubular containers is expensive and requires special equipment.
The formation of tubular containers from a longitudinally stretched, extruded, thermoplastic cylinder has been effected in an economical, efficient, and commercially viable method, such as described in U.S. Pat. No. 3,047,910 to Downs, and U.S. Pat. No. 5,069,856 to Holoubek & Rhoades. These methods are somewhat limited, however, in that a wall thickness of about 0.012 to 0.025 inch is about the maximum wall thickness that can be efficiently and economically achieved. Thus, such a method is generally not suited for producing thick walled tubes for use in a tubular container containing a self-sealing valve, as previously described.
It is an object of the present invention to provide a thermoplastic squeeze container containing a self-sealing dispensing valve the container having a side wall that is squeezable to dispense flowable material therefrom but having sufficient rigidity such that the side wall returns to a noncollapsed position upon release of pressure on the side wall so as to suck in and close the self-sealing valve.